(0.8.0)
parallel\Future::value — Resolution
Shall return (and if necessary wait for) return from task
Shall throw \parallel\Future\Error if waiting failed (internal error).
Shall throw \parallel\Future\Error\Killed if \parallel\Runtime executing task was killed.
Shall throw \parallel\Future\Error\Cancelled if task was cancelled.
Shall throw \parallel\Future\Error\Foreign if task raised an unrecognized uncaught exception.
Shall rethrow \Throwable uncaught in task